Satellite-based blockchain architecture

ABSTRACT

The present invention discloses a satellite-based blockchain architecture, including a terrestrial blockchain miner network, a constellation system, and a consensus protocol coordinating the constellation system and the terrestrial blockchain miner network. In each round, a satellite generates an oracle, and satellites broadcast the oracle to the terrestrial blockchain miner network. The oracle selects a terrestrial miner as a winner of the current round based on a specific rule. The winning terrestrial miner has the right to generate a new block in the round, and broadcasts the new block to other miners by using the terrestrial blockchain miner network. Other miners receiving the new block check the validity of the block, and if the check succeeds, the block is broadcast to other miners by using the terrestrial blockchain miner network. The present invention significantly improves the efficiency and throughput of a blockchain, and optimizes and reduces the energy consumption of executing a consensus protocol by a terrestrial blockchain miner network.

TECHNICAL FIELD

The present invention relates to the field of blockchains, andspecifically, to a satellite-based blockchain architecture.

BACKGROUND

In 2008, the birth of bitcoin sparked widespread attention amongfinancial practitioners. As the core technology behind bitcoin, ablockchain has gradually entered the field of vision of researchers. Asa public classified ledger and database, a blockchain has advantagessuch as decentralization, tamper resistance, openness and transparency,collective maintenance, trackability, and traceability. The consensusmechanism is the core of a blockchain, that is, a distributed ledgertechnology. A blockchain is based on a specific consensus mechanism anduses appropriate financial incentives to motivate miners in a blockchainnetwork to maintain an open and orderly ledger together. Proof of Work(PoW) was first proposed in 1992 and has become the most popularconsensus mechanism since the release of bitcoin in 2008, and the greatsuccess of PoW in the field of cryptocurrency is a testament to itsrobustness against misconduct and malicious attacks.

However, the PoW consensus mechanism consumes massive energy and wastesenormous resources. In existing alternatives to PoW, other capabilitiesof miners rather than the computational power required in PoW are usedfor mining. However, new potential security hazards are usually caused,and the existing blockchains will also suffer from serious scalabilityproblems due to the constraints of consensus mechanisms. Transactionsper second (TPS), a measure of the throughput of a blockchain, is quitelow in a conventional blockchain. There are at most 7 transactions persecond for bitcoin and at most 15 transactions per second for Ethereum.In comparison, centralized trading platforms such as PayPal and VISA mayreach network throughput of thousands of TPS. In short, high energyconsumption and low throughput are two main obstacles that severelylimit the development of blockchain technology.

Satellite technology has attracted the attention of more and moreresearchers for its advantages such as wide coverage, ubiquitousconnectivity, and stable downlinks. Currently, only a few research workshave discussed the applicability of satellites in blockchain. In mostexisting research works, satellites are used as relays to forward blocksto an area lacking a terrestrial blockchain miner network or deficientin terrestrial blockchain miner network services, or satellites are usedto accelerate the propagation of information in a terrestrial blockchainminer network. An uplink is the difficulty in such researches. Ordinaryusers need to use specific authorized ground stations to upload newlygenerated blocks, which raises the access threshold, increases the costsof using such services for ordinary users, and reduces thedecentralization of a blockchain.

SUMMARY

Inventive objective: To overcome main obstacles that limit thedevelopment of blockchain technology, the present invention provides asatellite-based blockchain architecture, to fully utilize advantagesthat satellite technology has wide coverage and can provide ubiquitousconnectivity, deeply integrate the blockchain technology and thesatellite technology, and use unique advantages of satellites to improvethe blockchain consensus mechanism, thereby reducing the waste ofresources and effectively improving the performance of blockchains. Inaddition, the consensus mechanism only utilizes the downlinks ofsatellites, so that the access threshold is greatly lowered for users,thereby further enhancing the decentralization of a blockchain.

To achieve the foregoing objective, the technical solutions adopted inthe present invention are as follows:

A satellite-based blockchain architecture includes a terrestrialblockchain miner network, a constellation system formed by a pluralityof satellites, and a consensus protocol coordinating the constellationsystem and the terrestrial blockchain miner network. In each round, asatellite generates an oracle, and broadcasts the oracle to theterrestrial blockchain miner network. The oracle selects a terrestrialminer as a winner of the current round based on a specific rule. Thewinning terrestrial miner has the right to generate a new block in theround, and broadcasts the new block to other miners by using theterrestrial blockchain miner network. A miner receiving the new blockchecks the validity of the block, and if the check succeeds, the blockis broadcast to other miners by using the terrestrial blockchain minernetwork.

The satellites include geostationary earth orbit satellites, mediumearth orbit satellites, and low earth orbit satellites. The terrestrialblockchain miner network includes more than one terrestrial miner. Theterrestrial miners are communicatively connected to each other vianetwork. The satellites are communicatively connected to each other vianetwork.

The consensus protocol coordinating the constellation system and theterrestrial blockchain miner network includes the following steps:

Step 1: A satellite generates an oracle in each round.

The satellite generates the oracle by using two methods, denoted as afirst oracle generation method and a second oracle generation method.

In the first oracle generation method, a satellite measures physicalquantities such as cosmic rays, hydromagnetic waves, and instantaneousradiations in real time by using satellite-borne measuring instruments,and numerical conversion is performed to generate the oracle. However,in this oracle generation manner, it is necessary to order and purchasecorresponding services from a satellite operator, leading to an increasein the maintenance cost. In the second oracle generation method,satellites are used to broadcast data packets for satellite television,a global positioning system or other specific use to the ground, andnumerical conversion is performed to generate the oracle. In thisgeneration manner, the satellite is not aware of the participation inthe generation of the oracle and the maintenance of a blockchain, andtherefore it is not necessary to purchase any satellite service.However, this manner may affect the randomness of the oracle, which ismore likely to be manipulated by malicious terrestrial miners.Therefore, a balance is to be reached between the security and cost interms of the generation of the oracle. During practical application, ageneration method should be selected according to objectives andrequirements of a blockchain.

Step 2: The satellites broadcast the oracle generated in step 2 to theterrestrial blockchain miner network. The broadcast oracle is digitallysigned by the satellite generating the oracle to prevent fraudulence,and subsequently the oracle is packed in a newly generated block forother terrestrial miners to verify the validity of the oracle.

Step 3: A terrestrial miner in the terrestrial blockchain miner networkreceives, by using a terrestrial receiving terminal, the oraclegenerated in step 2, and determines, according to a specific rule,whether the terrestrial miner is selected.

It is relatively risky to directly choose a terrestrial miner as awinner of a round according to the oracle. The reason is that amalicious miner may create a plurality of identities to initiate theSybil attack to increase a probability of being selected. The specificrule herein can adequately solve this problem.

The specific rule is the principle of the proof of stake consensusmechanism. The oracle is mapped to an index in a list of all currentexisting crypto-currencies, and an owner of a crypto-currencycorresponding to the index is a winner of a current round. Under therule, a probability that each miner wins is only related to acrypto-currency that the miner holds, and does not increase as aquantity of identities of the miner increases, thereby effectivelyresisting the Sybil attack.

Step 4: A selected terrestrial miner generates a new block at the top ofan existing blockchain, and broadcasts the new block to otherterrestrial miners by using the terrestrial blockchain miner network.

Step 5: A remaining terrestrial miner checks the validity of the newblock after receiving the new block; and if the check fails, discardsthe block; or if the check succeeds, continues to broadcast the block toother terrestrial miners by using the terrestrial blockchain minernetwork.

Through the broadcasting of the satellites and the forwarding in theterrestrial blockchain miner network, most terrestrial miners receivethe oracle, and after the validity of a new block is verified, thelength of the blockchain is increased by 1. This cycle is repeated, andthe blockchain grows as new blocks are built on original blocks.

According to different heights of motion orbits, the satellites mayinclude geostationary earth orbit satellites, medium earth orbitsatellites, and low earth orbit satellites. The geostationary earthorbit satellites are stationary relative to Earth's surface, the Dopplershift is ignorable, and a probability of a transmission interruption islower than a non-geostationary earth orbit satellite. In addition, thegeostationary earth orbit satellite works in an orbit at an altitude ofapproximately 35,786 kilometers. One geostationary earth orbit satellitecan cover one third of Earth's surface. With the advantages of lowprobability of transmission interruption and wide coverage, thegeostationary earth orbit satellite is a preferred satellite in thispatent.

In the case of a plurality of satellites, the consensus protocol gives apredefined protocol to determine the satellite used for generating anoracle in each round. In the first oracle generation method, theconsensus protocol determines a sequence in a pseudorandom manner, andthe satellites in the constellation system generate oracles in turnaccording to the sequence. In the second oracle generation method, theconsensus protocol gives a predefined protocol to determine a specificsatellite, and the satellite broadcasts a data packet for specific usein a specific time slot at a specific frequency band to generate theoracle.

Preferably, the terrestrial receiving terminal includes portable mobilereceivers or very small aperture terminals.

Compared with the prior art, the present invention can fully utilize thetechnical advantages of satellites to improve blockchain consensusmechanism, to provide the following beneficial effects:

-   -   1) Compared with the widely known PoW consensus mechanism, the        present invention greatly reduces the energy consumption of a        consensus process, thereby significantly improving the        throughput of blockchain.    -   2) The present invention deeply integrates satellite technology        and blockchain technology, and fully utilizes the advantages of        wide coverage, ubiquitous connectivity, and stable downlinks of        the satellite technology, thereby substantially improving the        efficiency of a consensus process.    -   3) Compared with existing researches of combining blockchain and        satellite, in the present invention, miners do not need to        access an uplink of satellites, so that the access threshold is        lowered for users, the deployment efficiency is greatly        improved, and miners only need to use devices that can receive        satellite broadcasting to access the satellite-based blockchain        architecture.    -   4) In the present invention, instead of performing complex        processing operations or generating, forwarding, storing, and        verifying a block, a satellite only needs to broadcast an        oracle, so that satellite-borne processing requirements and        launch costs are significantly reduced, which is conducive to        the promotion and popularization in the future.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a satellite-based blockchainarchitecture.

FIG. 2 is a schematic diagram of a working procedure of asatellite-based blockchain architecture.

FIG. 3 is a schematic diagram of a blockchain evolution mode of asatellite-based blockchain architecture.

FIG. 4 is a simulation diagram of relationships between normalizedthroughput and security of the blockchain and a proportion of maliciousterrestrial miners at different proportions of malicious satellites. Itcan be seen that when a proportion of malicious miners is higher, thenormalized throughput and the security of the blockchain are lower. Whenthe proportion of malicious satellites increases, the normalizedthroughput and the security of the blockchain also decrease.

FIG. 5 is a simulation diagram of relationships between normalizedthroughput and security of the blockchain and a proportion of maliciousentities (including malicious satellites and malicious miners) in theblockchain at different success probabilities of satellite transmission.It can be seen that when the proportion of malicious entities in theblockchain is higher, the normalized throughput and the security of theblockchain are lower.

FIG. 6 is a simulation diagram of a relationship between normalizedthroughput of the blockchain and the network transmission delay. It canbe seen that when the network transmission delay is lower, thenormalized throughput of the blockchain is higher.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present invention is further described below with reference to theaccompanying drawings and specific embodiments. It should be understoodthat these examples are intended only to describe the present inventionbut not to limit the scope of the present invention. Variousmodifications in equivalent form made to the present invention by thoseskilled in the art after reading the present invention all fall withinthe scope defined by the appended claims of the present application.

As shown in FIG. 1 and FIG. 2 , the satellite-based blockchainarchitecture includes a constellation system formed by threegeostationary earth orbit satellites, a terrestrial blockchain minernetwork formed by five terrestrial miners, and a consensus protocolcoordinating the constellation system and the terrestrial blockchainminer network.

-   -   1) A satellite measures physical data such as cosmic rays,        hydromagnetic waves, and instantaneous radiations in real time        by using satellite-borne measuring instruments, and integration        and numerical conversion are performed on the physical data to        generate an oracle.    -   2) The satellite broadcasts the oracle generated by the        satellite to the five miners in the terrestrial blockchain miner        network.    -   3) A terrestrial miner receives, by using a terrestrial        receiving terminal such as a portable mobile receiver and a        miniature-antenna Earth station, the oracle generated by the        satellite. As shown in FIG. 1 , according to the principle of        proof of stake, the lowermost terrestrial miner is selected in        the first round, and receives the oracle broadcast by the        satellite.    -   4) The terrestrial miner generates a new block, and broadcasts        the new block to other terrestrial miners by using the        terrestrial blockchain miner network.    -   5) A remaining terrestrial miner checks the validity of the new        block after receiving the new block. After the check succeeds,        the block continues to be broadcast to other terrestrial miners        by using the terrestrial blockchain miner network.

However, the network delay and the presence of misconduct of a satelliteor miner may lead to various emergencies. For ease of description ofvarious cases, FIG. 3 gives a schematic diagram of the blockchainevolution mode based on the novel blockchain consensus mechanism.

As shown in FIG. 3(a), in normal cases, according to the rule of proofof stake, a terrestrial miner w₂ is selected by an oracle as the winnerin the second round. w₂ receives the oracle broadcast by a satellite,and then w₂ collects transactions in the terrestrial blockchain minernetwork, verifies the transactions, and packs the transactions. Next, w₂generates a new block b₂ following a block b₁ generated by the winner Wtin the first round, and uses the terrestrial blockchain miner network tobroadcast b₂. b₂ includes a hash pointer pointing to b₂. When w₂ isselected in the third round, w₁ repeats a process similar to that of w₂to generate b₃. This cycle is repeated, and the blockchain keepsgrowing.

As shown in FIG. 3(b), in the second round, due to an interruption in asatellite link, the terrestrial miner w₂ fails to receive the oraclebroadcast by the satellite. Therefore, no new block is generated in thesecond round. In this case, the winning miner w₂, in the third rounddirectly generates one block b₂ pointing to the block b₁.

As shown in FIG. 3(c), when generating the new block the winning minerw₂ in the third round fails to receive the block b₂ broadcast by theminer w₂ due to the network delay. w₂ generates the block b₂. pointingto the block b₁. In this case, the blockchain forks, and a winner innext round determines whether or b₂ is finally included in the mainchain.

FIG. 3(d) reflects a case that the winning winner w in the second roundmay have misconduct, generating an invalid block b₂. FIG. 3(e) reflectsa case that the miner w₂, may forge an identity to generate an invalidblock b₂′. It is very easy to discover the foregoing two cases duringthe verification of the block by other nodes. Therefore, the invalidblocks in the two cases are both excluded from the main chain.

FIG. 3(f) reflects a case that the winning w₂ in the second round maypublish two new blocks at once, that is, the block b₂′ and a block b₂″,causing the blockchain to fork. Generally, honest miners discard suchblocks.

FIG. 3(g) reflects a case that a malicious miner may privately mine in afraudulent branch. When attacked transactions has been confirmed and thelength of the fraudulent branch exceeds the length of the current mainchain, the fraudulent branch is published, to achieve a“double-spending” attack.

Referring to FIG. 4 to FIG. 6 , to show the performance of the presentinvention during actual work, actual tests were performed and data wasrecorded for typical embodiments of the present invention. Analysisresults are as follows.

FIG. 4 reflects relationships between normalized throughput and securityof the blockchain and the proportion of malicious terrestrial miners atdifferent proportions of malicious satellites. If the proportion ofmalicious satellites is constant, when the proportion of maliciousminers in the terrestrial blockchain miner network is higher, thethroughput of the blockchain is lower, the error confirmationprobability is higher, and the security is lower. Similarly, if theproportion of malicious miners in the terrestrial miner network isconstant, when the proportion of malicious satellites is higher, thethroughput of the blockchain is lower, the error confirmationprobability is higher, and the security is lower.

FIG. 5 reflects relationships between normalized throughput and securityof the blockchain and the proportion of malicious entities in theblockchain at different success probabilities of satellite transmissionand comparison between the present invention and PoW in terms ofthroughput and security. The analysis results show that in the case ofthe same security performance, the present invention has higherthroughput compared with PoW. The throughput of the blockchain in thepresent invention largely depends on the quality of the satellitebroadcast channel, that is, the transmission success probability. As thequality of the satellite channel improves, the transmission successprobability is higher, and the throughput of the blockchain alsoincreases correspondingly.

FIG. 6 reflects the relationship between throughput of the blockchainand the information propagation delay at different transmission successprobabilities and different proportions of malicious entities. It can beseen that if the proportion of malicious entities is constant, when theproportion of new block miners is higher, the information propagationdelay of the terrestrial blockchain miner network is lower, and thethroughput of the blockchain is higher.

The present invention fully utilizes the advantages of wide coverage,ubiquitous connectivity, and stable downlinks of satellites to build asatellite-based blockchain architecture, so that the efficiency of theblockchain is significantly improved, and the energy consumption ofexecuting the consensus protocol by a terrestrial blockchain minernetwork is optimized and reduced. The blockchain consensus mechanism isimproved by fully utilizing the advantages of wide coverage, ubiquitousconnectivity, and stable downlinks of satellites, so that compared withthe conventional PoW consensus mechanism, the resource consumption isgreatly reduced, and the system throughput is significantly improved.

The foregoing descriptions are preferred implementations of the presentinvention. It should be noted that for a person of ordinary skill in theart, several improvements and modifications may further be made withoutdeparting from the principle of the present invention. Theseimprovements and modifications should also be deemed as falling withinthe protection scope of the present invention.

What is claimed is:
 1. A novel satellite-based blockchain architecture,comprising a terrestrial blockchain miner network, a constellationsystem, and a consensus protocol coordinating the constellation systemand the terrestrial blockchain miner network, wherein the terrestrialblockchain miner network comprises more than one terrestrial miner, andthe terrestrial miners are communicatively connected via a network; theconstellation system is formed by three or more satellites, thesatellites are communicatively connected to each other via a network,and the satellites and the terrestrial miners are communicativelyconnected to each other via a network; and the consensus protocolcoordinating the constellation system and the terrestrial blockchainminer network is used for generating an oracle by a satellite in theconstellation system and controlling the constellation system tobroadcast the oracle to the terrestrial blockchain miner network; acorresponding terrestrial miner in the terrestrial blockchain minernetwork has the right to generate a new block, and broadcasts the newblock to other terrestrial miners by using the terrestrial blockchainminer network; and other terrestrial miners receiving the new blockchecks the validity of the block, and if the check succeeds, the blockis broadcast to other terrestrial miners by using the terrestrialblockchain miner network.
 2. The novel satellite-based blockchainarchitecture according to claim 1, wherein the consensus protocolcoordinating the constellation system and the terrestrial blockchainminer network comprises the following working steps: step 1: generating,by a satellite, an oracle based on a specific scheme in each round; step2: broadcasting, by the satellites, the oracle to the terrestrialblockchain miner network, wherein the oracle is a random number used fordetermining a winning terrestrial miner in each round; step 3:receiving, by terrestrial miners by using terrestrial receivingterminals, the oracle generated in step 1, and determining, according toa specific rule, whether the terrestrial miner is selected; step 4:generating, by a selected terrestrial miner, a new block, andbroadcasting the new block to the other terrestrial miners by using theterrestrial blockchain miner network; and step 5: checking, the validityof the new block after the other terrestrial miners receive the newblock; and if the check fails, discarding the block; or if the checksucceeds, broadcasting the block to other terrestrial miners by usingthe terrestrial blockchain miner network.
 3. The novel satellite-basedblockchain architecture according to claim 2, wherein the satellitegenerates the oracle based on the specific scheme by using two methods,denoted as a first oracle generation method and a second oraclegeneration method; in the first oracle generation method, ageostationary earth orbit satellite measures cosmic rays, hydromagneticwaves, and instantaneous radiations in real time by usingsatellite-borne measuring instruments, and numerical conversion isperformed to obtain the oracle; and in the second oracle generationmethod, a satellite is used to broadcast a data packet for satellitetelevision, a global positioning system or other use to the ground, andnumerical conversion is performed to generate the oracle.
 4. The novelsatellite-based blockchain architecture according to claim 3, whereinthe specific rule comprises the following steps: mapping the oracle toan index in a list of currently generated crypto-currencies, and anowner of a crypto-currency corresponding to the index is a selectedterrestrial miner in a current round.
 5. The novel satellite-basedblockchain architecture according to claim 4, wherein in the firstoracle generation method, the consensus protocol determines a sequencein a pseudorandom manner, and the satellites in the constellation systemgenerate oracles in turn according to the sequence; and in the secondoracle generation method, the consensus protocol gives a predefinedprotocol to determine a specific satellite, and the satellite broadcastsa data packet for specific use in a specific time slot at a specificfrequency band to generate the oracle.
 6. The satellite-based blockchainarchitecture according to claim 5, wherein the satellites comprisegeostationary earth orbit satellites, medium earth orbit satellites, andlow earth orbit satellites.
 7. The novel satellite-based blockchainarchitecture according to claim 6, wherein the constellation systemprovides ultra-wide ground coverage, ubiquitous connectivity, and stabledownlinks.
 8. The satellite-based blockchain architecture according toclaim 7, wherein the terrestrial receiving terminal comprises a portablemobile receiver and a miniature-antenna Earth station.